Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS) analysis of volatiles from untreate...Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples(under the optimal conditions) of Paphia undulata enzymatic hydrolysate revealed that the compounds contributing to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodorizing effects of activated carbon(AC) adsorption, yeast extract(YE) masking and tea polyphenol(TP) treatment on a P. undulata enzymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption(35 mg mL^(-1), 80℃, 40 min), YE masking(7 mg mL^(-1), 45℃, 30 min) and TP treatment(0.4 mg mL^(-1), 40℃, 50 min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of aldehydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine(TMA) formation in a P. undulate hydrolysate solution for a period of 72 h.展开更多
In the present study, ultrasonic extraction technique(UET) is used to improve the yield of polysaccharides from Laminaria japonica(LJPs). And their antioxidative as well as glycosidase inhibitory activities are invest...In the present study, ultrasonic extraction technique(UET) is used to improve the yield of polysaccharides from Laminaria japonica(LJPs). And their antioxidative as well as glycosidase inhibitory activities are investigated. Box-Behnken design(BBD) combined with response surface methodology(RSM) is applied to optimize ultrasonic extraction for polysaccharides. The optimized conditions are obtained as extraction time at 54 min, ultrasonic power at 1050 W, extraction temperature at 80℃ and ratio of material to solvent at 1:50(g m L-1). Under these optimal ultrasonic extraction conditions, an actual experimental yield(5.75% ± 0.3%) is close to the predicted result(5.67%) with no significant difference(P > 0.05). Vitro antioxidative and glycosidase inhibitory activities tests indicate that the crude polysaccharides(LJP) and two major ethanol precipitated fractions(LJP1 and LJP2) are in a concentration-dependent manner. LJP2(30%-60% ethanol precipitated polysaccharides) possesses the strongest α-glucosidase inhibitory activity and moderate scavenging activity against hydroxyl radicals(66.09% ± 2.19%, 3.0 mg m L-1). Also, the inhibitory activity against α-glucosidase(59.08% ± 3.79%, 5.0 mg m L-1) is close to that of acarbose(63.99% ± 3.27%, 5.0 mg m L-1). LJP1(30% ethanol precipitated polysaccharides) exhibits the strongest scavenging activity against hydroxyl radicals(99.80% ± 0.00%, 3.0 mgm L-1) and moderate α-glucosidase inhibitory activity(47.76% ± 1.92%, 5.0 mg m L-1). LJP shows the most remarkable DPPH scavenging activity(66.20% ± 0.11%, 5.0 mg m L-1) but weakest α-glucosidase inhibitory activity(37.77% ± 1.30%, 5.0 mg m L-1). However, all these LJPs exert weak inhibitory effects against α-amylase. These results show that UET is an effective method for extracting bioactive polysaccharides from seaweed materials. LJP1 and LJP2 can be developed as a potential ingredient in hypoglycemic agents or functional food for the management of diabetes. This study provides scientific evidence and advances in the preparation technology and a hypoglycemic activities evaluation method for seaweed polysaccharides, especially glycosidase inhibition in combination with an antioxidative activity evaluation method.展开更多
In this study,seven coal-based activated carbons(ACs)were adopted to remove trimethylamine(TMA)in an aqueous solution as environmentally friendly and harmless adsorbents.The results showed that columnar AC(CAC)had a c...In this study,seven coal-based activated carbons(ACs)were adopted to remove trimethylamine(TMA)in an aqueous solution as environmentally friendly and harmless adsorbents.The results showed that columnar AC(CAC)had a clear scale and honeycomb structures with few fragments and micropores,contributing to superior TMA removal capacity compared to granular AC(GAC)(71.67%for 6.0 mm CAC and 69.92%for 40–60 mesh GAC).In addition,the process of adsorption was accompanied by desorption,and the recommended absorbed time was 120–180 min.The short time to achieve equilibrium indicated that adsorption was kinetically controlled,and pseudo-second-order kinetics was more appropriate than pseudo-first-order kinetics in explaining the adsorption mechanism in both water and oyster enzymatic hydrolysate.The intraparticle diffusion model presented that the adsorption processes could be divided into three steps for GAC and two steps for CAC.The adsorption processes were consistent with the Freundlich model,indicating the existence of physisorption and chemisorption as multilayer adsorption.The results indicated that AC,especially CAC,has great potential for TMA elimination in aquatic product processing.展开更多
基金supported by the Public Science and Technology Research Funds Projects of Ocean (No.201305018)the National Key Technology Research and Development Program for the 12th Five-Year Plan (No.2012BAD33B10)+3 种基金the National Natural Science Foundation of Guangdong, China (Nos. 2014A 030310351 and 2014A030310338)the Innovative Development of Marine Economy Regional Demonstration Projects of Guangdong (Nos.SZHY2012-B01-004 and GD2013-B03-001)the Science and Technology Planning Project of Guangdong Province, China (Nos.2013B 090800002 and 2015B090904003)the National Science Foundation for Young Scientists of China (No.31101271)
文摘Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples(under the optimal conditions) of Paphia undulata enzymatic hydrolysate revealed that the compounds contributing to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodorizing effects of activated carbon(AC) adsorption, yeast extract(YE) masking and tea polyphenol(TP) treatment on a P. undulata enzymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption(35 mg mL^(-1), 80℃, 40 min), YE masking(7 mg mL^(-1), 45℃, 30 min) and TP treatment(0.4 mg mL^(-1), 40℃, 50 min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of aldehydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine(TMA) formation in a P. undulate hydrolysate solution for a period of 72 h.
基金supported by the Project of National Key Technology Research and Development Program for the 12th Five-year Plan(No.2012BAD33B10)Public Science and Technology Research Funds Projects of Ocean(No.201305018-2)+4 种基金the Innovative Development of Marine Economy Regional Demonstration Projects(Nos.SZHY2012-B01-004,GD2013-B03-001)the National Scien-ce Foundation for Young Scientists of China(No.31101271)the Natural Science Foundation of Guangdong Province(Nos.2014A030310338,2014A030310351)the Comprehensive Strategic Cooperation Programs between the Guangdong Province and Chinese Academy of Sciences(No.2011B090300057)the Frontier Science Program for Young Scientists of South China Sea Institute of Oceanology,Chinese Academy of Science(No.SQ 201017)
文摘In the present study, ultrasonic extraction technique(UET) is used to improve the yield of polysaccharides from Laminaria japonica(LJPs). And their antioxidative as well as glycosidase inhibitory activities are investigated. Box-Behnken design(BBD) combined with response surface methodology(RSM) is applied to optimize ultrasonic extraction for polysaccharides. The optimized conditions are obtained as extraction time at 54 min, ultrasonic power at 1050 W, extraction temperature at 80℃ and ratio of material to solvent at 1:50(g m L-1). Under these optimal ultrasonic extraction conditions, an actual experimental yield(5.75% ± 0.3%) is close to the predicted result(5.67%) with no significant difference(P > 0.05). Vitro antioxidative and glycosidase inhibitory activities tests indicate that the crude polysaccharides(LJP) and two major ethanol precipitated fractions(LJP1 and LJP2) are in a concentration-dependent manner. LJP2(30%-60% ethanol precipitated polysaccharides) possesses the strongest α-glucosidase inhibitory activity and moderate scavenging activity against hydroxyl radicals(66.09% ± 2.19%, 3.0 mg m L-1). Also, the inhibitory activity against α-glucosidase(59.08% ± 3.79%, 5.0 mg m L-1) is close to that of acarbose(63.99% ± 3.27%, 5.0 mg m L-1). LJP1(30% ethanol precipitated polysaccharides) exhibits the strongest scavenging activity against hydroxyl radicals(99.80% ± 0.00%, 3.0 mgm L-1) and moderate α-glucosidase inhibitory activity(47.76% ± 1.92%, 5.0 mg m L-1). LJP shows the most remarkable DPPH scavenging activity(66.20% ± 0.11%, 5.0 mg m L-1) but weakest α-glucosidase inhibitory activity(37.77% ± 1.30%, 5.0 mg m L-1). However, all these LJPs exert weak inhibitory effects against α-amylase. These results show that UET is an effective method for extracting bioactive polysaccharides from seaweed materials. LJP1 and LJP2 can be developed as a potential ingredient in hypoglycemic agents or functional food for the management of diabetes. This study provides scientific evidence and advances in the preparation technology and a hypoglycemic activities evaluation method for seaweed polysaccharides, especially glycosidase inhibition in combination with an antioxidative activity evaluation method.
基金the National Key R&D Program of China(No.2018YFC0311202)the Key-Area Research and Development Program of Guang-dong Province(No.2020B1111030004)+4 种基金the Science and Technology Program of Guangzhou,China(Nos.201804010364 and 201804010321)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0406)the National Key R&D Program of China(No.2018YFC0311202)the Natural Science Foun-dation of Guangdong Province,China(Nos.2018A030313088,2018A030313626)the Academician Work-station Foundation for Young Scientists of Chinese Aca-demy of Sciences Guangzhou Branch(No.20180313).
文摘In this study,seven coal-based activated carbons(ACs)were adopted to remove trimethylamine(TMA)in an aqueous solution as environmentally friendly and harmless adsorbents.The results showed that columnar AC(CAC)had a clear scale and honeycomb structures with few fragments and micropores,contributing to superior TMA removal capacity compared to granular AC(GAC)(71.67%for 6.0 mm CAC and 69.92%for 40–60 mesh GAC).In addition,the process of adsorption was accompanied by desorption,and the recommended absorbed time was 120–180 min.The short time to achieve equilibrium indicated that adsorption was kinetically controlled,and pseudo-second-order kinetics was more appropriate than pseudo-first-order kinetics in explaining the adsorption mechanism in both water and oyster enzymatic hydrolysate.The intraparticle diffusion model presented that the adsorption processes could be divided into three steps for GAC and two steps for CAC.The adsorption processes were consistent with the Freundlich model,indicating the existence of physisorption and chemisorption as multilayer adsorption.The results indicated that AC,especially CAC,has great potential for TMA elimination in aquatic product processing.
